Fuel water separators are used in conjunction with internal combustion engines to remove small traces of water from the hydrocarbon fuel. Certain fuel-water separating devices are two stage units in which the fuel initially passes through a coalescing element where the water droplets are coalesced into larger sized globules which flow by gravity from the downstream side of the coalescing element for collection in a sump. The finer water droplets carried by the fuel through the coalescing element are removed by the separator stage, and again also flow downwardly by gravity along the upstream side of the separator stage for collection in the sump.
In the past, fuel-water separators have been of relatively expensive, non-disposable construction in which the coalescing element must be replaced periodically.
Spin-on oil filters, in which the filter is threaded onto a nipple in the engine block, are known. Oil filters of this type are adapted to removed solid particles from the fuel and generally consist of a single separating stage.